Botulinum Toxin Good Long-Term in Dystonia

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Note that this study was published as an abstract and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.

After at least 10 years of treatment, dystonia patients receiving botulinum neurotoxin (either Botox or Dysport) continued to achieve symptom relief at the same magnitude and at the virtually the same dose used at baseline, a study found.

Note that the treatment appeared to be safe, and about 6% of patients reported adverse events which lasted a mean of 25 days.

SYDNEY -- After at least 10 years of treatment, dystonia patients receiving botulinum neurotoxin (either Botox or Dysport) continued to achieve symptom relief at the same magnitude and at virtually the same dose used at baseline, researchers said here.

Using the standard assessment instrument -- the Tsui rotation score -- patients treated with Botox had a 1.5 score at baseline, which was reduced to 1.2 over the short term and 0.8 at the end of the study -- a significant difference from baseline, Francesca Morgante, MD, of the University of Messina in Sicily, Italy, told MedPage Today.

Scores for patients treated with Dysport declined from 1.75 at baseline to 1.5 in the long term Morgante noted in her poster presentation at the International Congress on Parkinson's Disease and Movement Disorders. Overall, the decline from baseline for all patients using botulinum neurotoxin was significant (P=0.01), she said.

"Overall, we can say this is a very safe treatment and a very stable treatment," Morgante said. "We may be seeing a little increase in the Dysport dose over time, but this did not reach statistical significance. We use about 100 to 120 Botox units and about 500 to 700 Dysport units for each treatment cycle," she explained.

In addition, "We have not found any long-term risk. We have used this treatment in patients who are as old as 90 years without problems," Morgante said.

She noted that this is the longest follow-up study to date of the use of botulinum neurotoxin in the treatment of cervical dystonia. "All these patients have been treated for more than 10 years. They have been treated an average of 14.5 years and we have included patients treated as long as 24 years."

Morgante said that the researchers were unable to discern any meaningful differences in the effect of the two drugs. "The severity scales appear to show a difference but we used Dysport in more severe cases so they naturally have higher severity scores. There was no significant difference between them in effectiveness. The magnitude of response is the same."

"These results are not surprising at all," commented David Shprecher, DO, director of the Sleep and Movement Disorder Division at the University of Utah in Salt Lake City. "I have worked with doctors who have had patients on botulinum toxin treatment for 10 to 15 years with a very good sustained response."

"Once doctors find the right dose, it looks like the majority of patients can be treated without changes in dosing," he told MedPage Today. "We look for a duration of 12 weeks. That is the mantra for botulinum toxin therapy."

Morgante noted that over the course of the study, the duration of treatment effect remained the same -- about 3 months. The researchers compared treatments at baseline using Tsui scores and then checked progress after four cycles -- about 1 year -- and again compared that to effectiveness after the last treatment, at least 10 years down the road.

"What we see is that the benefit is about the same 1 year after treatment and after 15 years of treatment," Morgante said. Similar reductions were seen in tremor scores, pain scores. and total Tsui scores, she noted.

The average age of the patients in the study was 59.5 years; 19 were women, 8 men. The mean duration of disease in these patients was 19.4 years. The mean number of injections during the treatment course was 33.8.

About 6% of patients reported adverse events which lasted a mean of 25 days. A total of 28 cases of dysphagia and 20 cases of neck weakness were reported over the course of the treatment, according to Morgante. Other adverse events were rare.

Morgante and Shprecher had no disclosures.

Reviewed by Robert Jasmer, MD Associate Clinical Professor of Medicine, University of California, San Francisco and Dorothy Caputo, MA, BSN, RN, Nurse Planner

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